MONTREAL – Voice over Internet protocol phone service sounds better and connects faster than the standard public-switched phone network (PSTN), says a new survey from a Montreal company.
Data collected over the last 12 months (July 2005 to July 2006) by Minacom show that VOIP service quality, according to its standards-based, single-ended service quality test system, increased steadily over the last year, with an average Mean Opinion Score (MOS) of 4.2, compared to 3.9 for the PSTN.
(MOS is a scale commonly used to describe speech quality, ranging from 1 [worst] to 5 [best], says Minacom).
Based on a MOS threshold of 3.6, only one out of 50 calls in North America were considered to be unacceptable – 1 in 10 worldwide – while greater than 85% of VoIP calls exceeded average PSTN quality over the same period, says the company’s press release.
According to the survey, calls over VOIP connected quicker overall – 8.2 seconds on average, compared to 8.9 seconds for those placed over the PSTN. Regionally, the PSTN was faster to connect for calls placed to North America (4.3 seconds vs. 5.7 for VOIP), while international calls connected faster with VOIP (8.7 vs. 10.4 seconds for PSTN). Linear regression indicates that VoIP is closing the gap, connecting 2 seconds faster in July 2006 than a year earlier.
"A recent Internet Phone quality study by Brix Networks indicated that 1 in 5 calls were classified as unacceptable, and that call quality was steadily declining. As this study may have created the impression that VOIP service is not capable of delivering PSTN-grade phone service, Minacom felt it should be clarified for both those in the VOIP industry, and individuals and enterprises considering VOIP service, that this report evaluated computer-to-computer (PC-PC) Internet phone service, similar to those offered by Skype, Google Talk, MSN and YahooMessenger," says the Minacom release. "The quality and service reliability of these applications does not compare to that of the VOIP phone services offered by telcos, cable operators, and broadband VOIP providers who carefully deploy, monitor and manage the quality of their services."
PC-PC VoIP quality is subject to many diverse impairments, including firewall settings, computer performance, antivirus installations, high-compression codecs, and Internet bandwidth shared with gaming, file downloads, web surfing and e-mail, adds Minacom. By contrast, VOIP offered by service providers is switched using telecom grade equipment, uses lower-compression codecs, and is prioritized over regular Internet traffic using sophisticated, standards-based multimedia telephone adapters, maintained and monitored by the operator.
Minacom’s tests were conducted over PSTN, managed broadband and cable VoIP lines, the same services offered to residential and enterprise customers by phone, cable and hosted VoIP providers.
"Minacom’s QoS Benchmark Reports are used by the ITU Quality of Service Development Group in studies summarizing global phone quality, published annually to carriers worldwide for the consistency and accuracy of the measurements reported. Minacom’s Public Termination Inventory (PTI) database, used by the DirectQuality R7 web-based test-OSS to automate the calls, contains over 200,000 far-end public numbers in 230 countries and administrative regions worldwide," says the release.
